While debate rages on Gristmill and elsewhere about whether biofuels are worth a damn ecologically, investors in agribusiness firms are quietly counting their cash.

As corn and soy prices approach all-time highs, driven up by government biofuel mandates, farmers are scrambling to plant as much as they can — and lashing the earth with chemicals to maximize yields.

At a Wall Street meeting on Tuesday, genetically modified seed/herbicide giant Monsanto promised investors even-higher-than-expected profits in fiscal year 2008. The company expects to rake in $1.3-$1.4 billion in gross profit from its Roundup herbicide alone (Monsanto had been previously expecting to make $1 billion from Roundup); and it’s looking for a cool $3.5 billion from its genetically modified seeds and traits.

The company said it’s seeing "strong early-season order patterns in its U.S. corn seed and traits business" — meaning farmers are scrambling to lay in supplies of GM corn and soy seed ahead of the spring planting season.

Below the fold, I’ll drill down a little into Monsanto’s announcement.

Use of "triple-stacked trait" seeds in the United States is surging. Monsanto has been pushing corn seeds with three different GM traits — Roundup tolerance plus two kinds of pesticides. Envision vast cornfields where nearly everything is dead except the corn plants. Writes the company: "Monsanto’s triple-stack trait product could be planted on 25-27 million acres in the United States, an increase of approximately 50 percent over the prior year."

Monsanto is making boatloads of cash on industrial-ag booms in Brazil and Argentina. The company seems to be openly establishing corn and soy seed monopolies down there. " Monsanto now estimates that Brazilian soybean farmers used its Roundup Ready technology on 55 percent of acres this season, an increase of 10 percent compared with planted acres in 2007," the report states.

As for Brazilian corn, "Monsanto confirmed that its corn brands, DEKALB, Agroceres and Agroeste, are expected to collectively hold share at 40 percent of the Brazilian corn seed market."

As for Argentina and its massive demand for corn seeds, Monsanto didn’t reveal its market share. However, it did boast that its insecticide-laced corn seed has increased its market share by 5 percentage points two years running; and also that it’s about to launch a "double-stacked" corn seed, featuring an insecticide and Roundup tolerance.